The present invention generally relates to a medical apparatus and procedure. The present invention particularly relates to an apparatus and procedure for protecting a port site opening in the wall of a body cavity and preventing electrosurgical injuries caused by capactive coupling.
Minimally invasive surgical techniques, such as laparoscopic surgery, typically include the use of a trocar assembly. A trocar assembly includes a trocar (sometimes referred to as an xe2x80x9cobturatorxe2x80x9d) positioned within the lumen of a cannula. The trocar and cannula are advanced through a body cavity wall so as to create a small hole or a port site wound therein. The trocar is then completely removed from the lumen of the cannula such that the cannula""s lumen provides an entrance for laparoscopic instruments into the interior of the body cavity. The body cavity is then insufflated with an inert gas, such as CO2, to provide easier access to the organs contained therein. Once the surgery is complete the cannula is completely removed from the port site wound to rapidly desufflate the body cavity.
Surgery performed by using minimally invasive techniques is generally associated with lower postoperative morbidity, shorter postoperative stay, less postoperative pain, decreased cost, and quicker recovery as compared to xe2x80x9copenxe2x80x9d or conventional surgical techniques (1,2,3,4). Because of the aforementioned advantages, these minimally invasive techniques are being applied to an increasing variety of all surgical procedures. For example, laparoscopic procedures for the resection of malignancies have emerged. In particular, laparoscopic colectomy for carcinoma of the colon has been developed, and it has been reported that the initial results of these procedures have advantages over operations performed in the traditional open manner (5,6,15). Moreover, it is hoped that the long term results of these procedures will be comparable, or better than, those performed in the traditional open manner.
However, the development of laparoscopic surgery for cancer has been hindered because of the major concern regarding the implantation of tumor cells in the port site wound (2,3,6,7). In fact, numerous port site recurrences have been documented in the medical literature heretofore, and subcutaneous metastases after laparoscopic resection of malignant tissue is associated with a decreased survival rate for patients who may have had a curative cancer (2,3,6,7). Specifically, the medical literature reports that the incidence of tumor cell implantation ranges from as high as 20% to as low as 0%(8), The studies generating the aforementioned data utilized highly skilled and experienced laparoscopic surgeons practicing at major university programs. However, in spite of utilizing highly skilled and experienced laparoscopic surgeons, the data indicates that the incidence of tumor cell implantation in the surgical wound is greater when employing laparoscopic techniques as compared to when conventional surgical techniques are used (i.e. 0.6% implantation incidence for conventional techniques (9) compared to 1% incidence for laparoscopic techniques (10 )).
Several mechanisms may be responsible for the above discussed implantation of tumor cells in the port site wound. For example, minimally invasive surgical techniques for treating cancer require the insertion and removal of laparoscopic instruments or cameras through the lumen of the cannula. In addition, these surgical techniques require that the cannula itself be moved relative to the port site wound such that the cannula is advanced further into, or withdrawn from, the body cavity (11). Moving the cannula in the above described manner facilitates a surgeon""s ability to optimally locate instruments within the body cavity thereby helping to ensure the successful completion of the medical procedure. However, the aforementioned manipulations of the laparoscopic instruments and cannula may result in the exposure of the port site wound to exfoliated cancer cells which creates a risk of implanting tumor cells in the walls of the port site wound (11, 12). In particular, exfoliated cancer cells may adhere to and thus contaminate a portion of the exterior surface of the cannula (11, 12). The contaminated portion of the exterior surface of the cannula may then be advanced into contact with the port site wound during insertion and removal from the port site wound (11, 12). This contact may dislodge the exfoliated cancer cells from the exterior surface of the cannula and thus cause the exfoliated cancer cells to be implanted in the port site wound (11,12).
Furthermore, studies have shown that a physician may undergo a significant learning curve before becoming proficient in the performance of laparoscopic surgery, such as cancer surgery (3, 13). As a result, a relatively inexperienced surgeon may have a tendency to manipulate or handle a tumor to a greater degree during a surgical procedure than an experienced surgeon. In addition, an inexperienced surgeon may have a tendency to insert and withdraw an instrument through the lumen of the cannula a greater number of times than an experienced surgeon. The above described increased manipulation of the instrument or the tumor can result in a greater incidence of tumor cell implantation in the port site wound (11,12).
Regardless of how these cells contaminate the wound, once implanted therein, viable tumor cells can cause a subcutaneous metastases or xe2x80x9cport/extraction site recurrencexe2x80x9d after the resection of malignant tissue. These xe2x80x9cport/extraction site recurrencesxe2x80x9d have delayed the advancement of laparoscopic cancer surgery (2, 6, 7, 8, 9, 10, 11, 12). Therefore, it is desirable to provide an apparatus which will protect a port site wound from tumor cell implantation while allowing a surgeon to optimally locate instruments within the body cavity for successful completion of the medical procedure.
Furthermore, laparoscopic surgery performed for general surgery, gynecological surgery, urological surgery, or any other intra-abdominal surgery is associated with a small but real incidence of port site wound infection (1). The infecting bacteria causing these illnesses can contaminate the port site wound in the same manner as discussed above with regard to tumor cell contamination, and these infections can increase a patient""s morbidity and consequently the length of a patient""s hospital stay, thereby considerably increasing their hospital bill.
Moreover, the use of electrosurgical techniques are increasingly being used in conjunction with laparoscopic techniques. While the combination of electrosurgical and laparoscopic techniques has many advantages, it is recognized that potentially serious electrosurgical injuries can occur during these types of laparoscopic operations. In particular, the overall incidence of recognized electrosurgical injuries is between one and two patients per 1,000 operations (16). However, the total incidence of these types of injuries (i.e. the sum of recognized and unrecognized injuries) may be significantly higher since the majority go unrecognized at the time of the electrical insult and commonly present three to seven days afterward with fever and pain in the abdomen. These injuries have significantly increased the cost of health care.
The pathophysiology of some of the electrosurgical injuries received during laparoscopic surgery appear to involve the property of capacitance (16). A capacitor exists whenever a nonconductor separates two conductors. During minimally invasive surgery procedures a capacitor situation may be created by a surgical instrument. For example, the active electrode used in electrosurgical procedures is surrounded by nonconductive insulation, and the nonconductive insulation is surrounded by conductive metal cannula thereby creating a capacitor. The capacitor can create an electrostatic field between the two conductors (i.e. the active electrode and the metal cannula). As a result, a current in one conductor can, through the electrostatic field, induce a current in the second conductor. For example, an electrical current in the active electrode can induce an electrical current in the metal cannula.
Another surgical system uses a plastic cannula rather than a metal cannula. In a plastic cannula system the electrode is surrounded by insulation, which is then surrounded by a plastic cannula. The patient""s conductive tissue completes the definition of a capacitor. In this situation, capacitance is reduced but not eliminated.
The worst situation with respect to problems caused by capacitance is one involving a xe2x80x9chybrid cannula systemxe2x80x9d. This occurs when a metal cannula is held in place by a plastic anchor or xe2x80x9ccollarxe2x80x9d. The metal cannula still creates a capacitor with the active electrode, but the plastic collar around the metal cannula prevents the current from dissipating through the abdominal wall. This capacitively coupled current may exit to adjacent tissue on its way to the patient""s return electrode. This can cause significant injury (17). A recent study has shown that burns caused by such capacitive coupling may occur in vivo and result in serious injury to internal organs which can increase a patient""s morbidity and even cause death (16).
As technology advances, new surgical procedures, such as remote laparoscopic surgery (i.e. robotic laparoscopic surgery), are being introduced and utilized in the field of minimally invasive surgery (14). During use of these new surgical procedures the sensory feedback to the surgeon is decreased since robotic xe2x80x9carmsxe2x80x9d and xe2x80x9chandsxe2x80x9d (under the surgeon""s control) manipulate the surgical instruments. The decrease in the surgeon""s tactile sensory feedback can be a disadvantage when performing laparoscopic surgery for cancer. This is true since tactile feedback helps the surgeon avoid unnecessary manipulation of a tumor which may result in the implantation of tumor cells in the wall of the port site wound (2).
Therefore, in light of the above discussion, it is apparent that an apparatus which allows unrestricted movement of the cannula relative to the port site wound while preventing port site wound tumor cell implantation, reducing the incidence of port site wound infection, and preventing electrosurgical injuries, is desirable. The present invention provides such an apparatus in the form of a sleeve which protects the port site wound. One advantage the present invention has over the prior art is that it can be retrofit to existing trocar assembly technology. More specifically, the sleeve of the present invention can be used with trocar assemblies which are currently commercially available to laparoscopic surgeons. Another advantage the present invention has over the prior art is that it allows the cannula to be advanced into and withdrawn from the port site wound while still protecting the port site wound from contamination by tumor or other types of cells. Moreover, once attached, the described invention adds only a minimal amount of bulk to the diameter of the trocar assembly and prevents electrosurgical injuries.
1. Lord et al., Dis. Col. Rect. 39(2):148 (1996)
2. Berman, Important Advances in Oncology1996, Laparoscopic Resection for Colon Cancer Cause for Pause, Vincent DeVita Ed., p. 231
3. Falk et al., Dis. Col. Rect. 36:28 (1993)
4. Liberman et al., Surg. Endo. 10:15 (1996)
5. Reiver et al., Dis. Col. Rect. 37:22 (Podium Abstract 1994)
6. Regier, Gen. Surg. Lap. News 8:1 (1995)
7. Greene, Semin. Lap. Surg. 2(3):153 (1995)
8. Kazemier, Surg. Endo. 9:216 (1995)
9. Reilly et al., Dis. Col. Rect. 39(2):200 (1996)
10. Jacquet et al., Dis. Col. Rect. 38(10):140 (1995)
11. Reymond et al., Surg. Endo. 11:902 (1997)
12. Allardyce et al., Dis. Col. Rect. 40(8):939 (1997)
13. Caushaj et al., Dis. Col. Rect. 37(4):21 (Podium Abstract 1994)
14. Med. Simula. Train., 1(2):7, 12-13, 20-28 (1996)
15. Fleshman et al., Dis. Col. Rect. 39(1):15 (1996)
16. Nduka etal., J. Amer. Col. Surg. 179:161 (1994)
17. Principles of Electrosurgery; Educational Booklet, Valleylab Inc. Pfizer Hospital Products Group, Boulder, Colo., p. 13 (1995)
In accordance with one embodiment of the present invention, there is provided a medical apparatus which includes a trocar assembly having a cannula and a trocar, wherein (1) the cannula has (i) a lumen defined therein and (ii) a length L1, (2) the trocar is positionable between a first trocar position and a second trocar position, (3) the trocar is positioned within the lumen of the cannula when the trocar is positioned at the first trocar position, and (4) the trocar is completely removed from the lumen of the cannula when the trocar is positioned at the second trocar position. The medical apparatus also includes a sleeve having (i) a passageway extending therethrough, (ii) a sealing member extending therefrom, and (iii) a length L2, wherein (1) the cannula is positionable between a first cannula position and a second cannula position, (2) the cannula is positioned within the passageway of the sleeve when the cannula is positioned at the first cannula position, (3) the cannula is completely removed from the passageway of the sleeve when the cannula is positioned at the second cannula position, and (4) the length L1 of the cannula is greater than the length L2 of the sleeve such that a portion of the cannula extends out of the passageway of the sleeve when the cannula is positioned at the first cannula position.
Pursuant to another embodiment of the present invention, there is provided a medical procedure which includes the steps of creating an opening in a wall of a body cavity and advancing a medical apparatus through the opening and into the body cavity. The medical apparatus includes (1) a sleeve having (i) a passageway extending therethrough, (ii) a sealing member connected thereto, and (iii) a length L2 and (2) a trocar assembly positioned within the passageway of the sleeve. The trocar assembly includes a cannula and a trocar, wherein (i) the cannula is completely removable from the passageway of the sleeve, (ii) the cannula has a lumen defined therein, (iii) the cannula has a length L1, (iv) the trocar is completely removable from the lumen of the cannula, and (v) the length L1 of the cannula is greater than the length L2 of the sleeve such that a portion of the cannula extends out of the passageway of the sleeve when the cannula is positioned within the passageway of the sleeve. The medical procedure also includes the step of positioning the sealing member to contact an interior surface of the body cavity.
Pursuant to yet another embodiment of the present invention there is provided medical apparatus which is positionable within an opening defined in a wall of a body cavity. The medical apparatus includes a trocar assembly having a cannula and a trocar, wherein (1) the cannula has a lumen defined therein, (2) the trocar is positionable between a first trocar position and a second trocar position, (3) the trocar is positioned within the lumen of the cannula when the trocar is positioned at the first trocar position, and (4) the trocar is completely removed from the lumen of the cannula when the trocar is positioned at the second trocar position. The medical apparatus also includes a sleeve having (i) a passageway extending therethrough and (ii) a sealing member extending therefrom, wherein (1) the sealing member is movable between (i) a advancement orientation in which the sealing member is positioned to facilitate advancement of the sleeve into the opening and (ii) a sealing orientation in which the sealing member is positioned in contact with an interior surface of the wall of the body cavity which surrounds a space defined between the opening of the body cavity and the sleeve and (2) the cannula is positioned within the passageway of the sleeve such that the cannula is movable in an axial direction relative to the sleeve when the sealing member is in the sealing orientation.
It is therefore an object of the present invention to provide a new and useful medical apparatus and medical procedure.
It is another object of the present invention to provide an improved medical apparatus and medical procedure.
It is still another object of the present invention to provide a new and useful medical apparatus and medical procedure for protecting a port site wound from tumor cell implantation or contamination with an infectious agent.
It is another object of the present invention to provide an improved medical apparatus and medical procedure for protecting a port site wound from tumor cell implantation or contamination with an infectious agent.
It is also an object of the present invention to provide a medical apparatus for protecting a port site wound having a sleeve which can be used with trocar assemblies which are currently commercially available to laparoscopic surgeons.
It is still another object of the present invention to provide a medical apparatus for protecting a port site wound which adds only a minimal amount of bulk to the diameter of a trocar assembly.
It is yet another object of the present invention to provide a medical apparatus and medical procedure which continuously protects the port site wound from tumor cell implantation, or contamination with an infectious agent, during the movement of a cannula relative to the port site wound.
It is yet another object of the present invention to provide a medical apparatus and medical procedure which continuously protects the port site wound from tumor cell implantation, or contamination with an infectious agent, during robotic surgery.
It is still another object of the present invention to provide a medical apparatus and medical procedure which prevents electrosurgical injuries caused by capacitive coupling.
The above and other objects, features, and advantages of the present invention will become apparent from the following description and attached drawings.